Supportive mother–child interactions promote the development of social-emotional competence. Poverty and other associated psychosocial risk factors have a negative impact on mother–child interaction. In spite of Latino children being disproportionately represented among children living in poverty, research on mother–child interactions among economically disadvantaged Latino families remains scarce and results are mixed. The current study used an ecological approach to examine the relationship between maternal cumulative risk, child developmental delay, observed and self-reported quality of the mother–child relationship, time spent in Head Start, and teachers’ and parents’ ratings of social-emotional competence among 106 Latino Head Start children and their mothers. Cumulative risk showed a negative association with observed maternal supportiveness and self-reported quality of the mother–child relationship. Cumulative risk had negative and positive indirect effects, respectively, on child social competence and problem behavior through perceived quality of the mother–child relationship. This association only occurred when parent ratings of child behavior were used. Time spent in Head Start moderated the association between observed maternal supportiveness and social competence. Practice or Policy: Implications for providers and researchers attempting to improve social-emotional competence in disadvantaged Latino children by enhancing positive and supportive parenting practice are discussed.